Miter saw having mechanism for adjusting tilting angle of circular saw blade

ABSTRACT

A miter saw including a base, turntable, and circular saw unit supported to the turntable. A turntable is rotatable about its axis. The turntable has a tilting motion support. A support section has a tilt section tiltingly movable relative to the tilt motion support, and pivotally movably supports the circular saw unit. A clamp shaft is provided for clamping the tilting section to the tilt motion support. A tilt amount fine control unit is provided for performing fine control to the tilting angle, and includes an arcuate gear teeth section provided at the tilt motion support, rotation shaft for moving the arcuate gear teeth, and adjustment knob supported on the clamp shaft for rotating the rotation shaft. A neck table section is provided at a front side of the turntable, and includes a digital display for displaying a lateral tilting angle of the circular saw unit.

BACKGROUND OF THE INVENTION

The present invention relates to a miter saw, and more particularly, tosuch a miter saw capable of performing tilt cutting in which a sidesurface of the circular saw blade extends obliquely relative to an uppersurface of a base section.

In a conventional table top circular saw, a workpiece such as a woodblock is mounted on a base section, and the workpiece is cut by acircular saw unit vertically movable above the base section. If theworkpiece is to be cut obliquely relative to a vertical plane, postureof the workpiece on the base section must be changed. Thus, workabilitymay be lowered.

Japanese Patent Application Publication No. 2000-254817 discloses amiter saw including a base section, a support section, and a circularsaw unit. The base section includes a base and a turntable mounted onthe base and rotatable about its axis. A workpiece is mounted on theturntable. The support section upwardly extends from the base sectionand is laterally tiltable. The circular saw unit is positioned above thebase section and is pivotally movably supported to the support section.The circular saw unit includes a circular saw blade and a motor forrotating the blade. Since the support section is pivotally movable inthe lateral direction, the circular saw blade is laterally tiltable.Thus, an angle defined between a side surface of the circular saw bladeand an upper surface of the base section can be changed.

In order to cut the workpiece at a desired tilting angle, a protractormust be provided at a pivot axis position so as to recognize therelative position between the base section and the circular saw unit. Inthis case, the tilting position is adjusted by observing a scale of theprotractor. As a result, inevitable large error results due to thevisual observation. It would be extremely difficult to accuratelyprovide the tilting angle at the rate of 0.1 degree.

Further, the circular saw unit may be tiltingly moved by its own weightbecause of the tiltable arrangement of the circular saw unit. Therefore,in order to set the circular saw unit at a desired tilting angle, thetilting angle of the circular saw unit must be set to a desired scaleangle while holding the circular saw unit with user's hand against theown weight. Then, the tilting angle must be fixed. This procedurerequires a skill and a labor for accurate positioning.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a mitersaw capable of providing a desired tilting angle of the circular sawunit with high accuracy and less labor even at a fine tilting angle, andcapable of providing clear visibility with respect to the tilting angle.

This and other object of the present invention will be attained by amiter saw including a base section, a circular saw unit, a supportsection, a clamp mechanism, and a tilt amount fine control unit. Thebase section supports a workpiece thereon, and has a tilt support. Thecircular saw unit rotatably supports a circular saw blade. The supportsection pivotally movably supports the circular saw unit at a positionabove the base section. The support section has a tilting sectionlaterally tiltingly movable together with the circular saw unit and issupported to the base section. The tilt support supports the tiltingsection in contact therewith. The tilting section is tiltingly movablealong a tilting locus. The clamp mechanism presses the tilting sectionagainst the tilt support for fixing a lateral tilting posture of thesupport section. The tilt amount fine control unit is disposed betweenthe tilting section and the tilt support.

Preferably, the tilt amount fine control unit includes an arcuatesection, a rotation shaft, and an adjustment knob. The arcuate sectionis provided at the tilting locus and is movable integrally with thetilting section. The rotation shaft is rotatably supported to the tiltsupport and is associated with the arcuate section for tiltingly movingthe tilting section. The adjustment knob is rotatably supported to thetilt support and is associated with the rotation shaft for rotating therotation shaft about an axis thereof.

In another aspect of the invention, there is provided a miter sawincluding the base, the circular saw unit, the a support section, arotatable lever that fixes the tilting section to the tilt support uponrotating operation, and a rotatable adjustment knob movable along withthe tilting section and associated with the tilt support.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of a miter saw as viewed from its frontside according to a first embodiment of the present invention;

FIG. 2 is a perspective view of the miter saw as viewed from its rearside according to the first embodiment;

FIG. 3 is a front view of the miter saw according to the firstembodiment;

FIG. 4 is a front view of the miter saw according to the firstembodiment, and particularly showing a tilting state of a circular sawunit;

FIG. 5 is a bottom view of the miter saw according to the firstembodiment;

FIG. 6 is a cross-sectional left side view of the miter saw according tothe first embodiment;

FIG. 7 is an enlarged cross-sectional right side view showing anessential portion of the miter saw according to the first embodiment;

FIG. 8 is a bottom view of a turntable in the miter saw according to thefirst embodiment;

FIG. 9 is a cross-sectional right side view showing an adjustmentmechanism for fine-adjusting the rotational position of the turntable inthe miter saw according to the first embodiment;

FIG. 10 is a sight-through view as viewed from the bottom for showingthe adjustment mechanism for fine-adjusting the rotational position ofthe turntable in the miter saw according to the first embodiment;

FIG. 11 is a view showing a lower face of the turntable in the miter sawaccording to the first embodiment;

FIG. 12 is a cross-sectional view showing a supporting arrangement forsupporting rotation of the turntable at a base in the miter sawaccording to the first embodiment;

FIG. 13 is a plan view showing a rotation amount detection unit in themiter saw according to the first embodiment;

FIG. 14 is an enlarged cross-sectional view showing a pin and a screwfor the rotation amount detection unit in the miter saw according to thefirst embodiment;

FIG. 15 is an exploded cross-sectional view showing the positionalrelationship between a tilt motion support and a tilt section in themiter saw according to the first embodiment;

FIG. 16 is a rear view showing the tilt section and a rotation amountdetection unit in the miter saw according to the first embodiment;

FIG. 17 is a view for description of the tilt section and an adjustmentmechanism for finely adjusting the tilting angle of the tilt section inthe miter saw according to the first embodiment;

FIG. 18 is a cross-sectional view taken along the line XVIII-XVIII ofFIG. 17;

FIG. 19 is a view showing a tilting amount detection unit in the mitersaw according to the first embodiment;

FIG. 20 is a cross-sectional view taken along the line XX-XX of FIG. 19;

FIG. 21 is a view showing the tilting amount detection unit in the mitersaw according to the first embodiment;

FIG. 22 is a cross-sectional view taken along the line XXII-XXII of FIG.19;

FIG. 23 is a plan view of a digital display in the miter saw accordingto the first embodiment;

FIG. 24 is a control circuit in the miter saw according to the firstembodiment;

FIG. 25 is a cross-sectional view taken along the line XXIV-XXIV of FIG.9;

FIG. 26 is a plan view showing the rotation amount adjusting mechanismfor the turntable in the miter saw according to the first embodiment;

FIG. 27 is a plan view showing the rotation amount adjusting mechanismfor the turntable, and particularly showing a temporary fixing positionin the miter saw according to the first embodiment;

FIG. 28 is a plan view showing the rotation amount adjusting mechanismfor the turntable, and particularly showing a fine-adjustment state inthe miter saw according to the first embodiment;

FIG. 29 is a plan view showing the rotation amount adjusting mechanismfor the turntable, and particularly showing a full fixing position inthe miter saw according to the first embodiment;

FIG. 30 is a rear view showing the mechanism for finely adjustingtilting angle of the circular saw unit in the miter saw according to thefirst embodiment;

FIG. 31 is a flowchart showing a processing routine for displayingrotation angle of a turntable and a tilting angle of a circular sawblade in the miter saw according to the first embodiment;

FIG. 32 shows a first modification and is a plan view of a mechanism forfine-adjusting rotation angle of the turntable;

FIG. 33 shows a second modification and is a cross-sectional view of amechanism for adjusting rotation angle of the turntable;

FIG. 34 is a bottom view of the second modification;

FIG. 35 is a frontal cross-sectional view of the second modification;

FIG. 36 shows a third modification and is a cross-sectional view of amechanism for adjusting tilting angle of the circular saw unit;

FIG. 37 shows a fourth modification and is a rear view of a mechanismfor adjusting tilting angle of the circular saw unit;

FIG. 38 is a rear view according to the fourth modification;

FIG. 39 shows a fifth modification and is a rear view of a mechanism foradjusting tilting angle of the circular saw unit;

FIG. 40 shows a sixth modification and is a rear view of a mechanism foradjusting tilting angle of the circular saw unit;

FIG. 41 shows a seventh modification and is a rear view of a tiltingamount detection unit;

FIG. 42 is a cross-sectional view taken along the line XLI-XLI of FIG.41;

FIG. 43 shows an eighth modification and is a rear view of a tiltingamount detection unit;

FIG. 44 shows a ninth modification and is a block diagram of a controlcircuit which is a modification to the control circuit of FIG. 24;

FIG. 45 shows a tenth modification and is a perspective view of a slidetype miter saw;

FIG. 46 is a block diagram showing two pulse trains generated in therotation amount detection unit according to the first embodiment; and

FIG. 47 is a block diagram showing two pulse trains generated in thetilting amount detection unit according to the first embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A miter saw according to a first embodiment of the present inventionwill be described with reference to FIGS. 1 through 31, 46 and 47. Asshown in FIG. 1, the miter saw 1 includes a base section 2 installed ona stand or a floor for mounting thereon a workpiece such as a wood, acircular-saw unit 4 that cuts a workpiece, and a support section 3supporting the circular saw unit 4 pivotally movably toward and awayfrom the base section 2 and laterally tiltably relative to the basesection 2.

As shown in FIG. 1, the base section 2 includes a base 11 serving as aground section, a turntable 21 and a fence 12. The turntable 21 issupported on the base 11 and is rotatable about its axis with respect tothe base 11. The turntable 21 cooperates with the base 11 to support aworkpiece such as a wood block. The fence 12 laterally extends over thebase 11 and is supported on the base 11. The fence 12 has an abutmentsurface extending in the lateral direction and facing frontward incontact with a side surface of the workpiece for positioning theworkpiece. In the following description, the facing side of the abutmentsurface is defined as the front side, the extending direction of thefence is defined as leftward/rightward or lateral direction, and aground side of the base 11 is defined as a lower side.

As shown in FIGS. 1 and 3, the base 11 includes a right base 11A and aleft base 11B interposing the turntable 21 therebetween. Each topsurface of each base 11A, 11B serves as a workpiece mounting surface. Asshown in FIGS. 3 and 5, the base 11 also includes an arcuate portion 16disposed between the right base 11A and the left base 11B and protrudingfrontward. The arcuate portion 16 has a peripheral side whose center iscoincident with a rotation axis of the turntable 21. As shown in FIG. 5,the peripheral side has a lower end formed with a plurality of lockinggrooves 16 a engageable with a protruding portion 26B of a lock lever 26described later.

The plurality of locking grooves 16 a are positioned at a predeterminedangles such as 15 degrees, 30 degrees and 45 degrees relative to areference axis (0 degrees) extending frontward from the rotation axis ofthe turntable 21 in a direction perpendicular to the fence 12. Further,as shown in FIG. 5, a linking portion 15 is provided for linking theright base 11A to the left base 11B at a position in directconfrontation with the installation spot such as a floor. The linkingportion 15 has a center region provided with a rotation support 19 forrotatably supporting the turntable 21. The rotation support 19 definesthe rotation axis.

As shown in FIGS. 1 and 3, the fence 12 includes a right fence 12A fixedto the right base 11A and a left fence 12B fixed to the left base 11B.These fences 12A, 12B have abutment surfaces in abutment with theworkpiece, and the abutment surfaces extend in a direction substantiallyperpendicular to the upper surfaces of the base 11 carrying theworkpiece. As shown in FIG. 3, the left fence 12B has a pivot shaft 12D,and a separate pivotable fence 12C is pivotally supported to the leftfence 12B through the pivot shaft 12D. Thus, as shown in FIG. 4, adirect abutment of a circular saw blade 123 described later in thecircular-saw unit 4 against the fence 12 can be avoided by pivotallymoving the pivotable fence 12C away from a locus of the blade 123, evenif the circular saw unit 4 is tilted laterally.

As shown in FIGS. 5 and 6, an arcuate outer gear teeth segment 20 isfixed with a screw 20A to an upper surface of the linking portion 15 ata position rearward of the rotation support 19. The arcuate outer gearteeth segment 20 is on an imaginary circle whose center is coincidentwith the central axis of the rotation support 19. A rotation amountdetection unit 51 (FIG. 11 and described later) is displaceable relativeto the arcuate outer gear teeth segment 20 for detecting an angularrotation amount of the turntable 21.

As shown in FIG. 1, the turntable 21 includes a circular table section22 interposed between the right and left bases 11A and 11B, and havingan upper surface on which a workpiece is mounted. The circular tablesection 22 defines therein a rotation axis of the turntable 21. Theturntable 21 also includes a neck table section 23 extending frontwardfrom the circular table section 22 and positioned above the arcuateportion 16. The upper surfaces of the circular table section 22 and theneck table section 23 are flush with the upper surface of the base 11. Asemicircular recess 24 is formed at the turntable 21. The semicircularrecess 24 is open at the upper surfaces of the circular table section 22and the neck table section 23 in a fusiform-shaped configuration, andhas a semi-circular contour in the vertical direction in conformancewith the contour of the circular saw blade 123. The upper opening iscovered with a fusiformed shaped slit plate 25 having a center portionformed with a slit 25 a which allows the circular saw blade 123 to passtherethrough when the circular saw unit 4 is pivotally moved toward theturntable 21.

A battery box 132 (FIG. 6) is disposed in the semi-circular recess andat a left side of the slit 25 a. The battery box 132 is adapted forsupplying electric current to a microcomputer 142 described later.

As shown in FIGS. 6 and 7, a rotation shaft section 28 is disposed at abottom of the semi-circular recess 24 and at a position in alignmentwith the center of the circular table section 22. The rotation shaftsection 28 is housed in a space defined by the rotation support 9 of thebase 11. The rotation shaft section 28 and the rotation support 9 areformed with through holes through which a bolt 32 extends so as to allowthe turntable 21 to be rotatable relative to the base 11 withoutdisassembly of the turntable 21 from the base 11.

A protrusion 23A (FIG. 1) protrudes from a left side of the neck tablesection 23. The protrusion 23A is abuttable against the left base 11Bwhen the turntable 21 is angularly rotated. A corresponding protrusionalso protrudes from a right side of the neck table section 23 so as tobe abuttable against the right base 11A. Thus, the turntable 21 isangularly rotatable relative to the base 11 within a range defined bythe abutments.

An adjustment unit 41 (FIG. 1) is provided at a front end of the necktable section 23 for adjusting angular rotational position of theturntable 21. As shown in FIGS. 7 and 8, a pin fixing portion 30 and ascrew fixing portion 31 protrude from a lower face of the turntable 21.Further, the rotation amount detection unit 51 (FIG. 8) in associationwith the outer gear teeth segment 20 of the base 11 is disposed belowthe pin fixing portion 30 and the screw fixing portion 31 for detectingthe angular rotation amount of the turntable 21.

As shown in FIGS. 5 and 6, a resilient lock lever 26 is fixed withscrews 27 to the lower surface of the turntable 21 at a position belowthe arcuate portion 16 and in front of the rotation shaft section 28.The lock lever 26 extends to a front end position of the adjustment unit41 (FIG. 8). The front end portion of the lock lever 26 is positionedbelow the adjustment unit 41, and is folded upwardly along a front endsurface of the adjustment unit 41. A push-down portion 26A is providedat the free front end of the lock lever 26. The lock lever 26 isprovided with an upward protrusion 26B at a position in confrontationwith a lower end face of the peripheral wall of the arcuate portion 16.The upward protrusion is engageable with a selected one of the pluralityof locking grooves 16 a formed at the lower end face of the arcuateportion 16. Accordingly, angular rotational position of the turntable 21is fixed by the engagement of the upward protrusion 26B with theselected one of the locking grooves 16 a, since the lock lever 26 isangularly moved together with the angular movement of the turntable 21.

As shown in FIGS. 9 and 10, the adjustment unit 41 includes a frontframe 42 with which a lock lever fixing pin 49 is laterally slidablysupported for avoiding engagement of the upward protrusion 26B with theone of the locking grooves 16 a. As shown in FIG. 25 the lock leverfixing pin 49 has a tip end portion formed with an annular fixing groove49 a. Further, a spring 50 is disposed over the lock lever fixing pin 49for urging the pin 49 rightward. A tongue 260 extends upwardly from aleft side of the lock lever 26. The fee end of the tongue 260 ispositioned in superposed relation to the slide locus of the lock leverfixing pin 49. Normally, the lock lever fixing pin 49 is biasedrightward by the biasing force of the spring 50. In this case, thetongue 26C is out of engagement from the annular fixing groove 49 a, sothat the upward protrusion 26B is engageable with one of the lockinggrooves 16 a. On the other hand, if the push-down portion 26A of thelock lever 26 is pushed down and the lock lever fixing pin 49 is pushedleftward in FIG. 25, the tongue 26 can be engaged with the annularfixing groove 49 a when the push-down portion 26A is released. As aresult, the engagement of the upward protrusion 26B with the one of thelocking grooves 16 a is prevented to allow the turntable 21 to be freelyangularly rotated to a desired angle.

As shown in FIGS. 8 through 10, the adjustment unit 41 further includesa fixing handle 43, an adjusting screw 44 and a table contact piece 45in addition to the lock lever fixing pin 49. The front frame 42 of theturntable 21 has a front wall 47 (FIG. 9) and a rear wall 48 (FIG. 9)and is formed with a front opening 42 a, and lateral holes. The fixinghandle 43 has a shaft portion 43A extending through the front opening 42a in frontward/rearward direction, and has an inner distal end pressurecontactable with the outer peripheral surface of the arcuate portion 16of the base 11. The adjusting screw 44 extends through the lateral holesin a direction perpendicular to the shaft portion 43A. The adjustingscrew 44 includes a shaft portion 44A and a pair of knobs 44B at bothends of the shaft portion 44A. The shaft portion 43A is formed with amale thread at a region crossing with the adjusting screw 44. Theadjusting screw 44 is also formed with a male thread at a regioncrossing with the shaft portion 43A.

The table contact piece 45 is movable between the front wall 45 and therear wall 48 and is selectively contactable with the front wall 45 inaccordance with the frontward movement of the table contact piece 45 orwith the rear wall 48 in accordance with a rearward movement thereof.The table contact piece 45 is formed with a first female thread 45 athreadingly engageable with the male thread of the shaft portion 43A,and a second female thread 45 b threadingly engageable with the malethread of the adjusting screw 44. The first and second female thread 45a and 45 b extend perpendicular to each other, and are not intersectedwith each other but are offset from each other in the verticaldirection. Thus, the fixing handle 43 and the adjusting screw 44 aredirected perpendicular to each other by way of the table contact piece45. The fixing handle 43 and the table contact piece 45 constituteengagement components.

As shown in FIGS. 9 and 10, springs 46 are juxtaposed laterally and areinterposed between the table contact piece 45 and the front wall 47 forpermitting the piece 45 to abut on the rear wall 48. By threadinglyadvancing the fixing handle 43, the shaft portion 43A is moved rearwardrelative to the piece 45. However, after the distal inner end of theshaft portion 43A abuts on the outer peripheral surface of the arcuateportion 16, the fixing handle 43 cannot any more. Instead, the piece 45is then moved frontward because of the threading engagement with theshaft portion 43A.

Each end of the adjusting screw 44 is provided with the knob 44Binterposing the front frame 42 therebetween. Therefore, the adjustingscrew 44 is not movable laterally, i.e., in its axial direction relativeto the front frame 42. By the rotation of the adjusting screw 44 aboutits axis, relative movement between the piece 45 and the shaft portion44A occurs. In this case, since the shaft portion 44A is immovable inits axial direction, the piece 45 is moved laterally within the frontframe 42. The angular rotational position of the turntable 21 is fixedat a predetermined position by the engagement of the upward protrusion26B with one of the locking grooves 16 a. However, the engagementbetween the upward protrusion 26B and the locking groove 16 a isprevented at positions nearby the particular locking grooves whichdefine angular rotation angle such as 0 degree, and 15 degrees in orderto perform fine angular position control of the turntable 21 nearbythese angles.

When the tip end of the shaft portion 43A is brought into tight contactwith the outer peripheral surface of the arcuate portion 16 a of thebase 11, the fixing handle 43 is considered to be integral with the base11. Therefore, the lateral movement of the table contact piece 45relative to the front frame 42 implies the lateral movement of the frontframe 42 relative to the base 11, i.e., a minute lateral angularmovement of the turntable 21 relative to the base 11.

As shown in FIGS. 12 and 13, the rotation amount detection unit 51includes a sealed housing 52 supported to the turntable 21. In thehousing 52, an amplifier including a first gear set 56 and a second gearset 58, a detected segment 60 and an optical sensor 62 are assembled.Shafts 57, 59 and 61 are disposed in and rotatably supported to thehousing 52. The first gear set 56 includes a first gear 56A and a secondgear 56B. The first gear 56A protrudes outwardly from the housing 52 andis meshedly engaged with the outer gear teeth segment 20. The secondgear 56B is coaxially with and integral with the first gear 56A and ismeshedly engaged with the second gear set 58. A diameter of the secondgear 56B is greater than that of the first gear 56A. The first andsecond gears 56A and 56B are rotatable about the shaft 57, and thesecond gear 56B and a major part of the first gear 56A are disposed inthe housing 52.

The second gear set 58 includes a third gear 58A and a fourth gear 58B.The third gear 58A is meshedly engaged with the second gear 56B. Thefourth gear 58B is coaxially with and integral with the third gear 58Aand is meshedly engaged with the detected segment 60. A diameter of thefourth gear 58B is greater than that of the third gear 58A. The thirdand fourth gears 58A and 58B are rotatable about the shaft 59 and aredisposed in the housing 52.

The detected segment 60 includes a fifth gear 60A meshedly engaged withthe fourth gear 58B, and a disc like detected element 60B coaxially withand integral with the fifth gear 60A. The detected segment 60 isrotatable about the shaft 61 and is disposed in the housing 52. The disclike detected element 60B is formed with a hundred of radial slits 60C.The optical sensor 62 has a pair of arms for supporting the disc likedetected element 60B therebetween. Slits 60C is detected at the arms fordetecting rotation angle of the disc like detected element 60B.

The optical sensor 62 includes two light emitting elements (not shown)and two light receiving elements (not shown) each positioned inconfronting relation to each light emitting element. The disc likedetected element 60B is positioned between the light emitting elementsand the light receiving elements. In accordance with the rotation of thedisc like detected element 60B, lights emitted from the two lightemitting elements pass through the respective slits 60C and reach thelight receiving elements, and are shut off by a solid region of the disclike detected element 60B alternately, the solid region being positionedbetween the neighboring slits 60C and 60C to generate optical pulses.

One of the pair of light emitting and receiving elements are angularlydisplaced from the remaining pair of light emitting and receivingelements in the circumferential direction of the disc like detectedelement 60B. The microcomputer 142 receives two pulse trains A and Bdisplaced from each other by 90 degrees as shown in FIG. 46corresponding to the angular displacement.

Since the two pulse trains A and B displaced from each other by 90degrees are detected, rotating direction of the disc like detectedelement 60B can be detected. In other words, the direction of theangular rotation of the turntable 21 can be detected, the directionbeing one of the clockwise direction and counterclockwise direction.

More specifically, regarding pulse trains A and B in FIG. 46, high leveland low level are designated by “1” and “0”, respectively. Assuming thatthe present pulse in the pulse train A is “0”, and the present pulse inthe pulse train B is “0”. Then, if the pulse in the pulse train A is“1”, whereas the pulse in the pulse train B is “0”, the angular rotatingdirection of the turntable 21 is assumed to be clockwise direction,i.e., rightward in FIG. 46. On the other hand, assuming that the presentpulse in the pulse train A is “0”, and the present pulse in the pulsetrain B is “0”, and if the pulse in the pulse train A is “0”, whereasthe pulse in the pulse train B is “1”, the angular rotating direction ofthe turntable 21 is assumed to be counterclockwise direction, i.e.,leftward in FIG. 46. Incidentally, the gear ratio of the rotation amountdetection unit 51 is set so as to provide rotation of the detectedsegment 60 by 72 degrees per every rotation of the turntable 21 by 1degree.

As shown in FIG. 13, in the rotation amount detection unit 51, a pinextension hole 53 and a screw fixing region 54 are formed at the housing52 in the vicinity of the first gear set 56. A pin 63 extends throughthe pin extension hole 53. The screw fixing region 54 has a C-shapeconfiguration having an open end part. As shown in FIG. 14, when a screw64 is attached to the screw fixing portion 31, the screw fixing region54 can be separated from the screw 64 as long as the screw 64 isunfastened. The open end part of the screw fixing region 54 allows therotation amount detection unit 51 to be pivotally moved while theunfastened screw 64 extends into the screw fixing portion 1. Thus, therotation amount detection unit 51 is pivotable with respect to theturntable 21 about a pin 63. Further, the pivot position of the rotationamount detection unit 51 can be fixed relative to the turntable 21 at adesired angle by fastening the screw 64. Incidentally, a spring 64A isinterposed between the screw 64 and the screw fixing portion 31 so thatthe spring 64A functions as a spring washer. Thus, reaction force isalways imparted on the screw 64 in its axial direction, which preventsthe screw 64 from being freely rotated about is axis. Consequently,accidental release of the screw 64 from the screw fixing portion 31 dueto vibration can be prevented even if the screw 64 is unfastened.

As shown in FIG. 11, the housing 52 has an abutment region 52A, and theturntable 21 has an abutment plate 21A protruding downward from thelower face of the turntable 21 and in confrontation with the abutmentregion 52A. A spring 55 is interposed between the abutment plate 21A andthe abutment region 52A when the rotation amount detection unit 51 isattached to the turntable 21. By the biasing force of the spring 55, thefirst gear 56A of the first gear set 56 is pressed against the outergear teeth segment 20. Accordingly, rattling of the first gear 56Arelative to the outer gear teeth segment 20 can be restrained, andconsequently, angular rotation of the turntable 21 relative to the base11 can be accurately detected.

As shown in FIGS. 6 and 7, the turntable 21 has a rear end provided witha tilting motion support 71. The support section 3 includes a tiltsection 74 tiltable relative to the tilting motion support 71.

As shown in FIG. 6, the tilting motion support 71 extends upward fromthe rearmost end of the turntable 21. As shown in FIG. 15, The tiltingmotion support 71 is formed with a support bore 72 positioned flush withthe upper surface of the turntable 21 and coaxially with the widthwisecenterline of the slit 25 a (FIG. 1). The tilt section 74 has a pin bolt76 inserted into the support bore 72, so that the tilt section 74 islinked to the tilting motion support 71. The tilting motion support 71has a wall in contact with the tilt section 74, and the wall is formedwith a circular recess 71 a. An arcuate inner gear teeth 77 is fixed tothe circular recess 71 a by a screw (not shown). The arcuate inner gearteeth 77 is on an imaginary circle whose center is coincident with acenter axis of the support bore 72.

As shown in FIG. 18, a slide wall 78 is provided at the tilt section 74and at a position in sliding contact with the tilting motion support 71.A pivot hole 75 is formed at an approximately center of the slide wall78, and the pin bolt 76 extends through the pivot hole 75. Thus, theslide wall 78 is in sliding contact with a contour edge of the circularrecess 71 a at the rear side of the tilting motion support 71 when thetilt section 74 is pivotally moved relative to the tilting motionsupport 71. A rear wall 74A extends rearward from an edge of the slidewall 78. That is, the rear wall 74A extends substantially in parallelwith the pin bolt 76, and in a direction from the tilting motion support71 to the tilt section 74.

As shown in FIG. 16, an arcuate elongated slot 79 whose contour isdefined by an arcuate rib 80 is formed in the tilt section 74 and at aposition rightward of the pivot hole 75 of the tilt section 74. Theelongated slot 79 is open at the surface of the slide wall 78, and islocated on an imaginary circle whose center is coincident with thecenter axis of the pivot hole 75. The tilting motion support 71 isformed with a clamp hole 73 threadingly engageable with a clamp shaft 81(described later). The clamp hole 73 is positioned in confrontingrelation to the elongated slot 79.

A tilting amount detection unit 101 is disposed leftward of the pivothole 75 and at a position surrounded by the slide wall 78 and the rearwall 74A. The tilting amount detection unit 101 is adapted for detectinga tilting amount of the tilt section 74 relative to the tilting motionsupport 71 in association with the arcuate inner gear teeth 77 providedtherein.

A pair of tilt support arms 84 extend upward from the tilt section 74 ata position above the pivot hole 75 for supporting the circular saw unit4. A tilt support pin 85 (FIG. 15) extends between the pair of tiltsupport arms 84,84 for connecting the circular saw unit 4 to the supportsection 3. A cover 87 (FIG. 2) is provided at the end of the rear wall74A for protecting the elongated slot rib 80, the tilting amountdetection unit 101, and the pin bolt 76. Therefore, these components 80,101 and 76 are not exposed to the atmosphere. An arm support 86 (FIG. 1)is provided at the left tilt support arm 84 for supporting an arm 127(described later, FIG. 1).

As shown in FIG. 18, the clamp shaft 81 has a tip end formed with a malethread for threadingly engaging with the clamp hole 73. Thus, a tiltablerange of the tilt section 74 relative to the tilting motion support 71is defined by a movable range of the clamp shaft 81 within the elongatedslot 79. In the depicted embodiment, the tiltable range is 45 degrees.

As shown in FIG. 18, the arcuate rib 80 defining the elongated slot 79extends rearward from the rear surface of the tilt section 74. A clamplever 82 is provided at a rear end of the clamp shaft 81. A spacer 83assembling therein a spring 83A is interposed between the clamp lever 82and the rear end face of the arcuate rib 80. Since the clamp shaft 81 isthreadingly engaged with the clamp hole 73 of the tilting motion support71, the clamp lever 82 and the spacer 83 are moved toward the tiltingmotion support 71 upon fastening the clamp shaft 81 in response to thepivotal motion of the clamp lever 82 about an axis of the clamp shaft81. Since the arcuate rib 80 which is a part of the tilt section 74exists between the spacer 83 and the tilting motion support 71, thearcuate rib 80 is nippingly interposed between the spacer 83 and thetilting motion support 71. Accordingly, a frictional force is generatedbetween the slide wall 78 and the tilting motion support 71 so that thetilt section 74 is fixed to the tilt motion support 71 at a desiredtilting posture. Thus, a clamp unit is constituted by the clamp shaft81, the clamp lever 82, the spacer 83 and the spring 83A. Because of theprovision of the spring 83A within the spacer 83, the clamp lever 82 isurged rearward relative to the tilting motion support 71 and the arcuaterib 80. Consequently, accidental pivotal motion of the clamp lever 82can be restrained to reduce rattling.

As shown in FIGS. 17 and 18, a tilt amount fine control unit 91 isdisposed nearby the clamp shaft 81 for finely controlling tilting amountof the tilt section 74 relative to the tilt motion support 71. The tiltamount fine control unit 91 includes an arcuate gear teeth 92 fixed tothe tilt section 74, a rotation shaft 93 meshedly engaged with thearcuate gear teeth 92, and an adjustment knob 94 meshedly engaged withthe rotation shaft 93. The arcuate gear teeth 92 is located on animaginary circle whose center is coincident with the center axis of thepivot hole 75. Further, the arcuate gear teeth 92 is fixed at a positionalong a radially outer edge of the elongated slot 79 (FIG. 17). Therotation shaft 93 is rotatably supported to the tilting motion support71 and extends rearward in a direction approximately parallel with theclamp shaft 81. The rotation shaft 93 includes a first gear 93A meshedlyengaged with the arcuate gear teeth 92. The rotation shaft 93 alsoincludes a second gear 93B having a diameter greater than that of thefirst gear 93A and provided at a rear end of the rotation shaft 93. Theadjustment knob 94 is coaxially with and rotatably disposed over theclamp shaft 81. The coaxial arrangement of the adjustment knob 94 withthe clamp shaft 81 can save a space, thereby improving implementation orpackaging of the tilt amount fine control unit 91.

Since the arcuate gear teeth 92 and the rotation shaft 93 are drivinglyconnected to each other, and since the rotation shaft 93 is connected tothe adjustment knob 94, the adjustment knob 94 is connected to thecircular saw unit 4 through the rotation shaft 93. Further, the clamplever 82 and the adjustment knob 94 provide a relationship that allowsan operator to operate the clamp lever 82 at his one hand and to operatethe adjustment knob 94 at his another hand. Therefore, for unclampingthe tilting position of the tilt section 74, operator's one hand canoperate the clamp lever 82 while operator's another hand can operate theadjustment knob 94. Accordingly, it is possible to prevent the circularsaw unit 4 from its excessive tilting motion due to its own weight uponunclamping. Further, it is possible to start fine adjustment to thetilting posture of the tilt section 74 immediately after the unclamping.

A third gear 94A meshedly engaged with the second gear 93B is providedintegrally and coaxially with the adjustment knob 94 at a position infront of the adjustment knob 94. Incidentally, since the arcuate gearteeth 92 is drivingly connected to the adjustment knob 94, theadjustment knob 94 continues rotating as long as the tilt section 74 istiltingly moved for tilting the circular saw unit 4.

Further, since the gear ratio between the third gear 94A and the secondgear 93B and between the first gear 93A and the arcuate gear teeth 92 isdesirably set, a small tilting angle of the circular saw unit 4 resultseven if the adjustment knob 94 is rotated at a large rotation angle.This facilitates the fine tilting angle control.

As shown in FIGS. 19 and 20, the tilting amount detection unit 101includes a sealed housing 102, an amplifier containing a first gear set106 and a second gear set 108, a detected segment 110 and an opticalsensor 112, those assembled in the housing 102. Shafts 107, 109 and 111are disposed in and rotatably supported to the housing 102. The firstgear set 106 is supported to the shaft 107 and includes a first gear106A and a second gear 106B. The first gear 106A protrudes outwardlyfrom the housing 102, and the protruding part extends through a bore(not shown) formed in the tilt section 74, and is meshedly engaged withthe arcuate inner gear teeth 77. The second gear I 06B is coaxially withand integral with the first gear 106A and is meshedly engaged with thesecond gear set 108. A diameter of the second gear 106B is greater thanthat of the first gear 106A. The first and second gears 106A and 106Bare rotatable about an axis of the shaft 107, and the second gear 106Band a major part of the first gear 106A are disposed in the housing 102.

The second gear set 108 includes a third gear 108A and a fourth gear108B. The third gear 108A is meshedly engaged with the second gear 106B.The fourth gear 108B is coaxially with and integral with the third gear108A and is meshedly engaged with the detected segment 110. A diameterof the fourth gear 108B is greater than that of the third gear 108A. Thethird and fourth gears 108A and 108B are rotatable about an axis of theshaft 109 and are disposed in the housing 102.

The detected segment 110 includes a fifth gear 110A meshedly engagedwith the fourth gear 108B, and a disc like detected element 110Bcoaxially with and integral with the fifth gear 110A. The detectedsegment 110 is rotatable about an axis of the shaft 111 and is disposedin the housing 102. The disc like detected element 110B is formed with ahundred of radial slits 110C. The optical sensor 112 has a pair of armsfor supporting the disc like detected element 110B therebetween. Slits110C is detected at the arms for detecting rotation angle of the disclike detected element 110B.

The optical sensor 112 includes two light emitting elements (not shown)and two light receiving elements (not shown) each positioned inconfronting relation to each light emitting element. The disc likedetected element 110B is positioned between the light emitting elementsand the light receiving elements. In accordance with the rotation of thedisc like detected element 110B, lights emitted from the two lightemitting elements pass through the respective slits 110C and reach thelight receiving elements, and are shut off by a solid region of the disclike detected element 110B alternately, the solid region beingpositioned between the neighboring slits 110C and 110C to generateoptical pulses.

One of the pair of light emitting and receiving elements are angularlydisplaced from the remaining pair of light emitting and receivingelements in the circumferential direction of the disc like detectedelement 110B. The microcomputer 142 receives two pulse trains A and Bdisplaced from each other by 90 degrees as shown in FIG. 47corresponding to the angular displacement.

Since the two pulse trains A and B displaced from each other by 90degrees are detected, rotating direction of the disc like detectedelement 110B can be detected. In other words, the tilting direction ofthe circular saw unit 4 can be detected, the direction being one of theclockwise direction and counterclockwise direction.

More specifically, regarding pulse trains A and B in FIG. 47, high leveland low level are designated by “1” and “0”, respectively. Assuming thatthe present pulse in the pulse train A is “0”, and the present pulse inthe pulse train B is “0”. Then, if the pulse in the pulse train A is“1”, whereas the pulse in the pulse train B is “0”, the tiltingdirection of the tilt section 74 is assumed to be clockwise direction,i.e., leftward in FIG. 47. On the other hand, assuming that the presentpulse in the pulse train A is “0”, and the present pulse in the pulsetrain B is “0”, and then if the pulse in the pulse train A is “0”,whereas the pulse in the pulse train B is “1”, the tilting direction ofthe circular saw unit 4 is assumed to be counterclockwise direction,i.e., rightward in FIG. 47. Incidentally, the gear ratio of the tiltingamount detection unit 101 is set so as to provide rotation of thedetected segment 110B by 72 degrees per every tilting angle of the tiltsection 74 by 1 degree.

As shown in FIG. 19, in the tilting amount detection unit 101, a pinextension hole 103 and a screw fixing region 104 are formed at thehousing 102 in the vicinity of the first gear set 106. A pin 113 extendsthrough the pin extension hole 103. The screw fixing region 104 has aC-shape configuration having an open end part. As shown in FIG. 22, whena screw 114 is attached to the screw fixing portion 104, the screwfixing region 104 can be separated from the screw 114 as long as thescrew 114 is unfastened. The open end part of the screw fixing region104 allows the tilting amount detection unit 101 to be pivotally movedwhile the unfastened screw 114 extends into the screw fixing portion104. Thus, the tilting amount detection unit 101 is pivotable withrespect to the tilt section 74 about a pin 113 within a range defined bythe size of the screw fixing region 104. Further, the pivot position ofthe tilting amount detection unit 101 can be fixed relative to the tiltsection 74 at a desired angle by fastening the screw 114. Incidentally,a spring 114A is interposed between the screw 114 and the tilt section74 so that the spring 114A functions as a spring washer. Thus, reactionforce is always imparted on the screw 114 in its axial direction, whichprevents the screw 114 from being freely rotated about is axis.Consequently, accidental release of the screw 114 from the tilt section74 due to vibration can be prevented even if the screw 114 isunfastened.

As shown in FIG. 19, the housing 102 has an abutment region 102A. Aspring 105 is interposed between the abutment region 102A and an annularrib defining the pivot hole 75 when the pivot amount detection unit 101is attached to the tilt section 74. By the biasing force of the spring105, the first gear 106A of the first gear set 106 is pressed againstthe arcuate inner gear teeth 77. Accordingly, rattling of the first gear106A relative to the arcuate inner gear teeth 77 can be restrained, andconsequently, tilting amount (pivot amount) of the tilt section 74relative to the tilting motion support 71 can be accurately detected.

Attachment of the tilting amount detection unit 101 to the tilt section74 may be difficult to achieve if the first gear 106A is biased to aposition to be engageable with the arcuate inner gear teeth 77. Forfacilitating the attachment work, the tilting amount detection unit 101is provisionally fixed, with the screw 114, to the tilt section 74 witha specific pivot posture where the spring 105 is compressed as shown inFIG. 21. This posture provides a sufficient space between the first gear106A and the arcuate inner gear teeth 77. Then, the screw 114 isunfastened, so that the tilting amount detection unit 101 is pivotallymoved toward the arcuate inner gear teeth 77 by the biasing force of thespring 105. Thus, the first gear 106A is brought into meshing engagementwith the arcuate inner gear teeth 77.

The circular-saw unit 4 includes a frame 121, a motor housing 122, ahandle 128, the circular saw blade 123, a saw cover 125 and a safetycover 126. The frame 121 is connected to the tilt support arm 84 throughthe tilt support pin 85. A spring (not shown) is interposed between theframe 121 and the tilt support arm 84 for biasing the frame 121upwardly. Thus, the circular saw unit 4 is at its uppermost position asa rest position in case of a non-cutting operation.

The motor housing 122 is disposed at the front side of the frame 121 foraccommodating a motor (not shown). The handle 128 is disposed at anouter peripheral surface and front side of the motor housing 122. A usergrips the handle 128 to move the circular saw unit 4 downward forcutting operation. The motor housing 122 rotatably supports a rotationshaft 124 to which the circular saw blade 123 is concentrically fixed.The saw cover 125 is adapted to cover an upper half of the circular sawblade 123. The safety cover 126 is pivotally movably supported to thesaw cover 125 and is protrudable from and retractable into the saw cover125 for selectively covering a lower half of the circular saw blade 123.The arm 127 serves as a pivot moving mechanism for the safety cover 126,and has one end attached to the safety cover 126. The arm 127 hasanother end attached to the arm support 86. A carry handle 129 (FIG. 2)is provided at an approximately center portion of the frame 121 forhand-carrying the miter saw 1.

As shown in FIG. 1, a digital display such as a liquid crystal display131 is provided immediately above the adjustment unit 41. As shown inFIG. 23, the digital display 131 displays the angular rotation angle ofthe turntable 21 at a rate of 0.2 degrees, and displays the tiltingangle of the circular saw unit 4 at a rate of 0.5 degrees. Therefore,even fine or minute angular rotation angle and the tilting angle can beaccurately and easily recognized by the user. Generally, the user ispositioned in front of the miter saw for cutting operation. Since thedigital display 131 is provided at the front side of the miter saw 1,the user can easily recognize the displayed angle.

The digital display 131 displays the angles based on output signalstransmitted from the microcomputer 142. The microcomputer 142 includes acomputing means that performs computation based on the detection made bythe units 51 and 101. FIG. 24 shows a control circuit 140. To themicrocomputer 142, are connected a EEPROM 143, a Miter encoder 144, abevel encoder 145, AC/DC converter 146, a regulator 147, a battery box132 and the digital display 131.

The EEPROM 143 is adapted for electrically rewriting a content. TheMiter encoder 144 is adapted for converting a signal from the opticalsensor 62 of the rotation amount detecting unit 51 into a signalavailable for the microcomputer 142. The Bevel encoder 145 is adaptedfor converting a signal from the optical sensor 112 of the tiltingamount detecting unit 101 into a signal available for the microcomputer142. The AC/DC converter 146 is adapted for converting alternate currentfrom a main power source into direct current. The regulator 147 isadapted for regulating or stabilizing an electric power. The battery box132 and the AC/DC converter 146 are also connected to the Miter encoder144, the Bevel encoder 145, and the digital display 131 for supplyingelectric power thereto. An electric power supply is controlled such thatif a main power source through the AC/DC converter 146 is rendered OFF,an electric power from the battery box 132 is supplied to thesecomponents 144,145 and 131. On the other hand, if the main power sourceis rendered ON, an electric power from the main power source is suppliedto these components 144,145, 131. Incidentally, the electric power fromthe battery box 132 is not supplied to the motive component such as themotor (not shown), but is only supplied to the microcomputer 142, theMiter encoder 144, the Bevel encoder 145 for the purpose of a controland measurement.

A Miter reset switch 148 for resetting the angular rotation of theturntable 21, a Bevel reset switch 149 for resetting the tilting angleof the tilt section 74, and a backlight switch 150 for lighting abacklight of the digital display 131 are also connected to themicrocomputer 142. The digital display 131 is adapted for displaying aresult of computation executed in the microcomputer 142 based on theoutputs from the optical sensors 62, 112.

Cutting operation with the miter saw 1 will next be described. First,the workpiece is mounted on the upper surface of the base 11 while theworkpiece is pushed onto the abutment surface of the fence 12. Then, thecircular saw unit 4 is moved downward by pulling the handle 128 forcutting. For the cutting, the angled cutting is intended in which acutting face is angled with respect to the abutment surface of the fence12, or a slant cutting is intended in which a cutting face is slantedwith respect to the upper surface of the base 11. For these cuttings,the following procedures are taken.

If the workpiece is to be cut with a cutting face angled with respect tothe abutment surface of the fence 12, the turntable 21 is angularlyrotated. Since the circular saw unit 4 is positioned above the turntable21, the circular saw unit 4 is moved together with the turntable 21.Since the fence 12 is fixed to the base 11, the side surface of thecircular saw blade 123 is angled relative to the workpiece as viewedfrom the above point of the workpiece. This cutting mode will bereferred to as “angled cutting mode”.

In the angled cutting mode, a cutting angle can be determined by theengagement of the upward protrusion 26B with one of the locking grooves16 a. For the engagement, the turntable 21 is angularly rotated whilethe lock lever 26 is not pressed down. Then, the upward protrusion 26Bis brought into engagement with the desired one of the locking grooves16 a at the desired angle. With this state, the fixing handle 43 isfastened until the fixing handle 43 cannot be rotated any more,whereupon the tip end of the fixing handle 43 is pressed against thearcuate portion 16 of the base 11. Thus, the turntable 21 is fixed tothe base 11. In this state, the angular rotation angle of the turntable21 relative to the base 11 is precisely determined by the engagementbetween the locking groove 16 a and the upward protrusion 26B.Therefore, fine adjustment to the angular rotation of the turntable 21is not required.

For setting the cutting angle at a desired angle offset from thepredetermined angles defined by the locking grooves 16 a, the push-downportion 26A of the lock lever 26 is pushed down. Further, as shown inFIG. 25, the lock lever fixing pin 49 is pushed into a space within theframe 42, so that the tongue 26C is engaged with the annular fixinggroove 49 a. With this engagement, the engagement of the upwardprotrusion 26B with one of the locking grooves 16 a is prevented even ifthe upward protrusion 26B is vertically in alignment with the lockinggroove 16 a. Thus, the angular rotation angle of the turntable 21 can beset at a desired angle. After the tongue 26C is engaged with the annularfixing groove 49 a, the turntable 21 is angularly rotated to a positionnear the desired angle in the miter saw 1 according to the firstembodiment, the angular rotation angle can be displayed at every 0.2degrees. Therefore, a desired angular rotating position of the turntable21 cannot be easily provided by gripping the fixing handle 43 and movingthe fixing handle 43. Therefore in the present embodiment, after theturntable 21 is angularly rotated to a position near the desired angle,then, a fine adjustment is performed to accurately provide the desiredangle.

More specifically, as shown in FIG. 26, the adjustment unit 41 providedat the turntable 21 is positioned near the desired angle relative to thearcuate portion 16 provided at the base 11. In this state, the tip endof the fixing handle 43 is separated from the outer peripheral surfaceof the arcuate portion 16, and further, the table contact piece 45 is inabutment with the rear wall 48 by the biasing force of the spring 46.This position of the table contact piece 45 is referred to as a releaseposition.

Then in FIG. 27, the fixing handle 43 is rotated about its axis so as topress the tip end of the fixing handle 43 against the arcuate portion16. Thus, the table contact piece 45 is moved away from the rear wall 48to an adjustment position or a temporary fixing position because of thethreading engagement of the male thread at the fixing handle 43 with thefemale thread in the piece 45. In this case, the fixing handle 43functions as a base abutment member as well as a fixing mechanism.Further, the table contact piece 45 is spaced away from the front wall47, and the fixing handle 43 in threading engagement with the tablecontact piece 45 is pressed against the arcuate portion 16 because ofthe reaction force of the spring 46. In this condition, the relativeposition among the fixing handle 43, the table contact piece 45, and thearcuate portion 16 is fixed. However, the table contact piece 45 is notdirectly fixed to the frame 42, but is merely supported within the frame42 by means of the spring 46. Therefore, as shown in FIG. 28, relativeposition between the frame 42 and the table contact piece 45 can bechanged by rotating the adjustment screw 44 about its axis. In otherwords, the position of the frame 42 in the angular rotating direction ofthe turntable 21 relative to the fixing handle 43 and the table contactpiece 45 can be finely adjusted, the fixing handle 43 having beenimmovable in the angular rotating direction because of the intimatecontact of the tip end of the fixing handle 43 with the arcuate portion16. The fine adjustment can be performed within a length of the frontopening 42 a in the angular rotating direction as shown in FIG. 28through which the shaft portion 43A of the fixing handle 43 extends. Inthe depicted embodiment, plus minus 2 degrees are set in terms of theangular rotation amount of the turntable 21 for the fine adjustment.

Upon angular rotation of the turntable 21, the rotation amount detectionunit 51 is moved relative to the outer gear teeth segment 20. Thismoving amount is converted into the rotation amount of the first gearset 56 including the first gear 56A. The rotation angle of the firstgear set 56 is amplified at the second gear set 58 and the detectedsegment 60, such that the angular rotation of 1 degree of the turntable21 will cause angular rotation of 72 degrees of the detected segment 60.Since the disc like detected element 60B is formed with 100 slitsarrayed in a circumferential direction, 20 slits stand for 72 degrees.Further, the detected element 20B enables detection of a minimum angularrotation of 0.05 degrees for the turntable 21.

Furthermore, the miter saw 1 generates cutting chips during cuttingoperation. However, the components of the detection unit 51 includingthe first gear set 56 and the optical sensor 62 are housed in the sealedhousing 52, entry of the cutting chips into the housing 52 can beprevented. Consequently, precise detection of angular rotation of theturntable 21 can result. Thus, the turntable 21 can be moved to aprecise angular rotational position by the manipulation to the adjustingscrew 44 while observing the angle display at the digital display 131.

After the fine adjustment to the angular rotational position of theturntable 21, the fixing handle 43 is further clamped. As a result, thespring 46 is compressed, and as shown in FIG. 29, the table contactpiece 45 is moved to its full fixing position where the table contactpiece 45 is in abutment with the front wall 47 projecting from the frame42. In this state, relative position between the frame 2 and the tablecontact piece 45 cannot be changed in spite of the rotation of theadjusting screw 44, since the table contact piece 45 is tightly pressedagainst the front wall 47. Accordingly, the displacement of the frame 42relative to the arcuate portion 16 is prevented. (The arcuate portion 16has been integrally with the table contact piece 45 through the fixinghandle 43). Consequently, the displacement of the turntable 21associated with the frame 42 relative to the base 11 associated with thearcuate portion 16 does not occur. Thus, the accurate angular rotatingposition of the turntable 21 can be promptly set and the set angle canbe maintained for the angled cutting.

Next, if the cutting face on the workpiece is to be slanted with respectto the upper surface of the base 11 (hereinafter simply referred to asslant cutting), the circular saw unit 4 is slanted as shown in FIG. 4.As described above, the circular saw unit 4 is supported to the tiltsection 74. The clamp shaft 81 is unfastened to release abutment betweenthe slide wall 78 and the tilt motion support 71 so as to allow the tiltsection 74 to be tiltable relative to the tilt motion support 71.Accordingly, the circular saw unit 4 becomes tiltable because of its ownweight. With this state, the side surface of the circular saw blade 123is slanted relative to the upper surface of the workpiece.

In the slant cutting at a desired tilting angle, the circular saw unit 4is maintained at a tilting angle near a desired tilting angle byoperator's hand (FIG. 30). Then, the adjusting knob 94 is rotated togradually pivotally move the tilt section 74 about an axis of the pinbolt 76 so as to position the circular saw unit 4 at its desired tiltingangle. Then, the clamp lever 82 is operated to fix the tilt section 74to the tilting motion support 71. Accordingly, accurate positioning isachievable with respect to the tilting angle of the circular saw unit 4.After fastening the clamp lever 82, the rotation of the rotation shaft93 is prevented, since the arcuate gear teeth 92 is immovable.

By the pivotal movement of the tilt section 74, the tilt amountdetection unit 101 is moved relative to the arcuate inner gear teeth 77.The moving amount of the unit 101 is converted into a rotation amount ofthe first gear 106A of the first gear set 106. The rotation angle of thefirst gear 106A is amplified at the second gear set 108 and the detectedsegment 110 such that the pivot angle of 1 degree of the tilt section 74will cause angular rotation of 72 degrees of the detected segment 110.Since the disc like detected element 110B is formed with 100 slitsarrayed in a circumferential direction, 20 slits stand for 72 degrees.Further, the detected element 110B enables detection of a minimum pivotangle of 0.05 degrees for the tilt section 74.

Furthermore, the miter saw 1 generates cutting chips during cuttingoperation. However, the components of the detection unit 101 includingthe first gear set 106 and the optical sensor 112 are housed in thesealed housing 102, entry of the cutting chips into the housing 102 canbe prevented. Consequently, precise detection of pivot angle of the tiltsection 74 can result. Thus, the tilt section 74 can be pivotally movedto a precise pivot position while observing the angle display at thedigital display 131.

After the fine adjustment to the pivot position of the tilt section 74,the clamp shaft 81 is rotated by the clamp lever 82 so as to fix thetilt section 74 to the tilting motion support 71. As a result, theaccurate tilting posture of the circular saw unit 4 can be promptly setand the set posture can be maintained for the slant cutting at thedesired slant angle.

Next, a control routine for angle display at the digital display 131will be described in case of the angled cutting and slant cutting. Thedetection of the angular rotation amount and the pivot angle can be madeby an electrical power supplied from the battery box 132.

When a battery is assembled into the battery box 132, a control shown inFIG. 31 is started. Then, the angular rotation angle (Miter) and tiltingangle (Bevel) held in a RAM are set to zero (S1). The RAM is a memoryaccommodated in the microcomputer 142. Then, the routine proceeds intoS2 where optical pulse count value at the optical sensors 62 and 112 areset to zero.

Then, the microcomputer 142 performs detection as to the connection toAC power source (S03). If the AC power source has not been connected(S03:No), the routine proceeds into S7, where power supply to thedigital display 131 is stopped to stop angle display, and the backlightis shut off if the backlight switch 150 had been turned ON for lightingthe backlight, and then the routine goes into S08. On the other hand, ifconnection of AC power source is confirmed (S03:Yes), the routine isadvanced into S04 where a predetermined angle (the above “0” degree) isdisplayed and the routine goes into S05. In S05, judgment is made as towhether or not the backlight switch 150 had been turned ON. If thebacklight switch 150 has been rendered ON (S05:Yes), the backlight isturned ON (S06), and then the routine is proceeded into S08. If thebacklight switch 150 had not been turned ON (S05:No), the routineproceeds into S08.

In S08, existence of optical pulse at the optical sensor 112 isdetected. Non detection of the optical pulse (S08;No) impliesnon-rotation of the detected segment 110 formed with the slits 110C,which implies that the tilt section 74 is not pivotally moved and thusthe circular saw unit 4 is not tilted. Therefore, the routine is skippedinto an angular rotation angle detection routine starting from S17 whileneglecting the subsequent tilting angle detection routine from S09 toS16. On the other hand, if optical pulse is detected (S08:Yes), theroutine proceeds into S09.

In S09, tilting direction of the circular saw unit 4 is detected. If thecircular saw unit 4 is tilted leftward as viewed from the front of themiter saw 1, that is, if the tilt section 74 is pivoted relative to thetilting motion support 71 in the counterclockwise direction (S09:No),the routine proceeds into S11 where the pulse numbers corresponding tothe tilting angle are added. Then, the routine proceeds into S12 wherean angle to be displayed on the digital display 131 is computed. On theother hand, if the circular saw unit 4 is tilted rightward as viewedfrom the front of the miter saw 1, that is, if the tilt section 74 ispivoted relative to the tilting motion support 71 in the clockwisedirection (S09:Yes), the routine proceeds into S10 where the pulsenumbers corresponding to the tilting angle are subtracted. Then, theroutine proceeds into S12 where an angle to be displayed on the digitaldisplay 131 is computed. More specifically, addition or subtraction ismade at every 0.05 degrees relative to the angle stored in the RAM insuch a manner that detection of 20 pulses at the disc like detectedelement 110B amounts to the tilting angle of 1 degree. After thecomputation of the display angle in S12, the routine proceeds into S13where the display angle is stored into the RAM.

Then, in S14, judgment is made as to whether or not the Bevel resetswitch 149 is turned ON. The Bevel reset switch 149 is adapted forresetting the tilting angle up to S13 to zero. If the Bevel reset switch149 is not turned ON (S14:No), the routine proceeds into S17 in order tostart angular rotation angle display routine. On the other hand, if theBevel reset switch 149 is turned ON (S14:Yes), the routine proceeds intoS15 where the optical pulse count value is set to zero, and then thevalue stored in the RAM is cleared to zero in S16. Then, the routineproceeds into S17.

S17 through S25 pertain to process for angular rotation amount displayfor the turntable 21. In S17, existence of optical pulse at the opticalsensor 62 is detected. Non detection of the optical pulse (S17;No)implies non-rotation of the detected segment 60 formed with the slits60C, which implies that the turntable 21 is not angularly rotated.Therefore, the routine is returned back to S03 neglecting the subsequentangular rotation amount display routine from S18 to S25. On the otherhand, if optical pulse is detected (S17:Yes), the routine proceeds intoS18.

In S18, angular rotating direction of the turntable 21 is detected. Ifthe turntable 21 is rotated in counter-clockwise direction as viewedfrom the top of the miter saw 1 (S18:No), the routine proceeds into S20where the pulse numbers corresponding to the rotation amount aresubtracted. Then, the routine proceeds into S21 where a rotation angleto be displayed on the digital display 131 is computed. On the otherhand, if the turntable 21 is rotated in the clockwise direction asviewed from the top of the miter saw 1, (S18:Yes), the routine proceedsinto S19 where the pulse numbers corresponding to the rotation amountare added. Then, the routine proceeds into S21 where an angle to bedisplayed on the digital display 131 is computed. More specifically,addition or subtraction is made at every 0.05 degrees relative to theangle stored in the RAM in such a manner that detection of 20 pulses atthe disc like detected element 60B amounts to the rotation angle of 1degree. After the computation of the display angle in S21, the routineproceeds into S22 where the display angle is stored into the RAM.

Then, in S23, judgment is made as to whether or not the Miter resetswitch 148 is turned ON. The Miter reset switch 148 is adapted forresetting the rotation angle up to S22 to zero. If the Miter resetswitch 148 is not turned ON (S23:No), the routine proceeds into S03 inorder to repeat the above described processing routine. On the otherhand, if the Miter reset switch 148 is turned ON (S23:Yes), the routineproceeds into S24 where the optical pulse count value is set to zero,and then the value stored in the RAM is cleared to zero in S25. Then,the routine proceeds into S03 to repeat the above-described processingroutine.

Incidentally, the process from S17 to S25 for the rotation angledisplaying routine can be executed prior to the process from S08 to S16for the pivot angle displaying routine. Alternatively, consequentialsteps S08 to S16 and another consequential steps S17 to S25 can beperformed almost simultaneously through a multi-task processing.

The above-described processing is always executed as long as an electricpower is supplied from the battery box 132 even if a main AC powersource is not connected, and therefore, angular rotation amount of theturntable 21 and the tilting angle of the circular saw unit 4 can bealways recognized. That is, those angles in the former cutting operationcan be maintained. In other words, the miter saw 1 can be promptlyoperated without initial adjustment of the rotation angle and thetilting angle when the AC power source is connected if these angles forthe former cutting operation is still available for the subsequentcutting operation. Further, an electric power level supplied from thebattery box 132 is dependent on the power storage amount in the batteryin the battery box 132. If the storage amount becomes vacant, the powersupply will be stopped. In order to avoid this problem, a control can bemade to shut off the power supply from the battery box 132 and to startpower supply from the AC power source to the control circuit when the ACpower source is connected. This control can also be made to start powersupply from the battery box 132 if the AC power source is thendisconnected.

The miter saw according to the present invention is not limited to theabove-described embodiments, but various modifications may beconceivable.

FIG. 32 shows a first modification pertaining to the adjustment unit 41,wherein like parts and components are designated by the same referencenumerals and characters as those shown in the foregoing embodiments. Inthe first modification, a single spring 152 is interposed between atable contact piece 151 (corresponding to the table contact piece 45)and the front wall 47 instead of two springs 46. This modification canreduce components or parts that constitute the adjustment unit 41.

A second modification pertaining to the adjustment unit is shown inFIGS. 33 through 35. The arcuate portion 16 of the base has a lowersurface at its outer peripheral side, and the lower surface is formedwith gear teeth 153 facing downward. A frame 154 of the turntable isprovided with a support portion 154A extending downward therefrom, and afemale thread extending frontward/rearward is formed in the supportportion 154A. The shaft portion 43A of the fixing handle 43 isthreadingly engaged with the female thread. By rotating the fixinghandle 43 about its axis in one direction, the tip end of the fixinghandle 43 is brought into abutment with the arcuate portion 16 so as tofix the position of the frame 154 relative to the arcuate portion 16.

An adjustment member 155 is disposed over the shaft portion 43A, andrides over the support portion 154A. A spring 156 is disposed over theshaft portion 43A and interposed between a front surface of the supportportion 154A and the adjustment member 155 for urging the adjustmentmember 155 frontward. The adjustment member 155 has a rear endintegrally provided with a gear wheel 155A meshedly engageable with thegear teeth 153. The adjustment member 155 has a front end integrallyprovided with a knob 155B.

Fine adjustment for the rotational position of the turntable 21 usingthe adjustment member 155 will be described. After the turntable 21having the frame 154 is rotated to a position near the predeterminedrotation angle, the adjustment member 155 is pressed rearward to allowthe gear wheel 155A to be meshingly engaged with the gear teeth 153.While maintaining this meshing engagement, the knob 155B is rotatedabout its axis to perform fine control. Then, the fixing handle 43 isfastened, so that the position of the frame 154 relative to the arcuateportion 16 is fixed at the desired rotational position of the turntable21.

A third modification pertaining to a fine adjustment to the tiltingangle will be described with reference to FIG. 36 wherein like parts andcomponents are designated by the same reference numerals as those shownin FIGS. 18. A spring 164 is interposed between a fine adjustment knob163 and a clamp lever 161 for normally urging the fine adjustment knob163 rearward through a spacer 162, so that the slide wall 78 of the tiltsection 74 is urged toward the tilt motion support 71. Thus, frictionforce is generated between the slide wall 78 and the tilt motion support71.

If the intimate contact of the slide wall 78 to the tilt motion support71 is released upon unfastening the clamp lever 161, the circular sawunit 4 is urged to be tiltingly moved due to its own weight. However,this tilting motion due to the own weight can be restrained because ofthe friction force still imparted between the slide wall 78 and thetilting motion support 71 by the biasing force of the spring 164.

Further, free rotation of the fine adjustment knob 163 is restrainedbecause of the biasing force of the spring 164 is imparted on the knob163. Accordingly, a tilting movement of the tilt section 74 is alsorestrained since the tilt section 74 is connected to the fine adjustmentknob 163 through the rotation shaft 93. Thus, tilting motion of thecircular saw unit 4 due to its own weight can be restrained. This meansthat it is unnecessary to manually support the circular saw unit 4 at agiven posture by user's hand during fine adjustment to the tilting angleof the circular saw unit 4. This facilitates the fine adjustment.

A fourth modification pertaining to a fine adjustment to the tiltingangle will be described with reference to FIGS. 37 and 38. A shaftsupport 169 is rotatably supported in a peripheral side of the turntableat a position below the tilt section 74. A fine adjustment shaft 167 hasone end connected to the shaft support 169, so that the fine adjustmentshaft 167 is pivotally movable about an axis of the shaft support 169.The fine adjustment shaft 167 has an intermediate portion formed with aworm 166 selectively engageable with the arcuate gear teeth 92. The fineadjustment shaft 167 has a free end integrally provided with a fineadjustment knob 168. A stop 170 extends from the peripheral side of theturntable so as to limit the pivotal movement of the fine adjustmentshaft 167 in a direction away from the arcuate gear teeth 92.

Normally, the fine adjustment shaft 167 is in abutment with the stop170, so that the worm 166 is disengaged from the arcuate gear teeth 92as shown in FIG. 37. If the circular saw unit 4 is to be tiltingly movedto a desired tilting angle position, the fine adjustment shaft 167 ispivotally moved toward the arcuate gear teeth 92 so as to engage theworm 166 with the arcuate gear teeth 92 as shown in FIG. 38, after thecircular saw unit 4 is tiltingly moved to a position near the desiredtilting angle position. By this engagement, tilting posture of thecircular saw unit 4 can be maintained. Then, the fine adjustment knob168 is rotated about its axis so that the arcuate gear teeth 92 is movedabout the axis of the pivot bolt 76. The movement of the arcuate gearteeth 92 implies the tilting movement of the tilt section 74 about theaxis of the pivot bolt 76. Thus, the tilting angle of the circular sawblade 123 can be subjected to fine adjustment. Then, the clamp lever 82is fastened to fixedly secure the tilting angle.

Since the fine adjustment knob 168 is movable to the engagement positionin meshing engagement with the arcuate gear teeth 92 and to anon-engagement position in out of engagement therefrom, the worm 166 isonly engaged with the arcuate gear teeth 92 when the fine tilting anglecontrol is required. In other words, resistive force is not applied whenthe circular saw unit is tiltingly moved prior to the fine adjustment.

A fifth modification pertaining to a fine adjustment to the tiltingangle will be described with reference to FIG. 39. An arcuate elongatedslot 171 is formed longer than that of the elongated slot 79, so thatthe tilt section 74 can be tiltable to the angle of about 45 degrees inboth clockwise and counterclockwise directions. Thus, the circular sawunit 4 can be tilted to about 45 degrees in rightward and to 45 degreesin leftward.

A sixth modification pertaining to a fine adjustment to the tiltingangle is shown in FIG. 40. According to the modification, an arcuateelongated slot 171′ is positioned along an outer peripheral edge of thetilt section 74.

A seventh modification pertaining to a tilting amount detection unit isshown in FIGS. 41 and 42. A tilting amount detection unit 172 includes ahousing 172A in which rotation shafts 174 and 178 are rotatablysupported. A shaft support 179 is attached to the housing 172A forrotatably supporting a rotation shaft 176.

A first gear set 173, a second gear set 175 and detected segment 177 arecoaxially mounted on the shafts 174, 176, 178, respectively. Geometricalrelationship among the rotation shafts 174,176,178 is such that a lineconnecting the rotation shafts 174 and 178 is assumed to be a base lineof a triangle, and the rotation shaft 176 is at an apex of the triangle.The shaft support 179 is movable in a direction perpendicular to theline connecting the rotation shafts 174 and 178 and perpendicular to therotation shaft 176 as shown by arrows A1 and A2. Further, the shaftsupport 179 can be fixed to the housing 172A by screws 175. An opticalsensor 180 is provided beside the detected segment 177.

For assembly, the shaft support 179 is urged in the direction A1 (towardthe line connecting the rotation shafts 174 and 178) so as to maintainmeshing engagement of the second gear set 175 with the first gear set173 and the detected segment 177. Then, the screws 180 are fastened tofix the shaft support 179 to the housing 172A. With this arrangement,any rattling among the first gear set 173, the second gear set 175 andthe detected segment 177 does not occur. Accordingly, accurate rotationamount of the detected segment 177 in response to the rotation of thefirst gear set 173 can be obtained, thereby enhancing detection accuracyat the optical sensor 180. A modification is conceivable to the seventhmodification such that the shaft support 179 is not fixed to the housing172A, and a biasing member such as a spring is provided for biasing theshaft support 179 in the direction A1.

An eighth modification pertaining to a tilting amount detection unit isshown in FIG. 43. According to this modification, the spring 105 in thetilting amount detection unit 101 (FIG. 19) is dispensed with. Thetilting amount detection unit 101 is pivotally moved about the axis ofthe pin 113 so as to meshingly engage the first gear 106A with thearcuate inner gear teeth 77. Then, the screw 114 is fastened to maintainthe meshing engagement without rattling. Thus, the position of thetilting amount detection unit 101 can be fixed relative to the arcuateinner gear teeth 77, thereby accurately detecting the tilting angle ofthe tilt section 74 relative to the tilting motion support 71.

A modification pertaining to a tilting amount detection unit will bedescribed. A low output and low power consumption motor (not shown) isdrivingly coupled to the rotation shaft 111 or 178 of the detectedsegment 110 or 177 so that positive rotation force is imparted on theshaft 111 or 178. By the rotation force, the rotation shafts 107, 109 or174,176 are urged to be rotated. However, since the first gear 106 or173 is engaged with the arcuate inner gear teeth 77, and since rotationtorque of the motor is extremely small, the detected segment, the firstgear set and the second gear set are not rotated. Still however, becauseof the application of the rotational force by the motor, no rattlingoccurs between engaging regions. Further, even if relative movementoccurs between the arcuate inner gear teeth 77 and the tilting amountdetection unit 101 by the tilting motion of the tilt section 74, themotor does not affect the relative movement, since the output of themotor is extremely small. Furthermore, because of the employment of thelow power consumption motor, power from the battery box 132 can be usedfor energizing the motor even if the main power source is not connected.

The above-described modifications to the tilting amount detection unitare also available for the rotation amount detection unit 51. Further,in the above-described embodiments, gears are used for transmittingrotation to the detected segment. Here, friction wheels can be usedinstead of the gears for amplifying and transmitting rotation.

A ninth modification pertaining to a control circuit is shown in FIG.44. In the control circuit shown in FIG. 24, the battery box 132 isprovided for continuously measuring rotation amount of the turntable 21and tilting amount of the circular saw unit 4. However, in the controlcircuit shown in FIG. 44, the battery box 132 is dispensed with. In thelatter case, if the turntable 21 is angularly rotated or the circularsaw unit 4 is tiltingly moved while the AC power source is disconnected,computation of such angle cannot be made in the microcomputer 142. Evenif the AC power source is connected thereafter, the rotation amount andtilting amount is unknown. To avoid this problem, a notice as to thenecessity of zero resetting can be displayed on the digital display 131.After the turntable 21 is set to zero angle position, and after thecircular saw unit 4 is set to zero angle position in response to thenotice by the display 131, Miter reset switch 148 and the Bevel resetswitch 149 are pressed for initialization. Then, the turntable isangularly rotated or the circular saw unit 4 is tiltingly moved.

Further, the set position of the battery box 132 is not limited towithin the semi-circular recess 24, but can be disposed at the lowersurface of the base 11.

A tenth modification is shown in FIG. 45. In the miter saw 1 accordingto the foregoing embodiments, the support section 3 pivotally movablyextends from the base section 2 and is pivotally movably supports thecircular saw unit 189. In a miter saw 181, a tilt support portion 184integrally extends from a turntable 183. A support section 185corresponding to the support section 3 includes a holder section 186, aslide section 187, and a saw unit support section 188.

The holder section 186 has a lower end pivotally movably supported to aturntable 183. A pivot axis of the holder section 186 is coincident withan upper surface of the turntable 183 and with a slit 191 a of a slitplate 191 at a neck table section 190 of the turntable 183. The slit 191a is adapted to allow a circular saw blade 192 to be inserted thereinwhen the circular saw unit 189 is moved toward the turntable 183. Apivot posture of the holder section 186 is changed and fixed relative tothe tilt support section 184. The holder section 186 has an upper endportion provided with a slide guide portion 186A.

The slide section 187 has guide bars (not shown) movable infrontward/rearward direction and slidably supported by the slide guideportion 186A. The saw unit support section 188 is provided at a frontend of the guide bars. The circular saw unit 189 is pivotally movablysupported to the saw unit support section 188 through a support pin188A. Thus, by the sliding movement of the slide section 187 relative tothe holder section 186, the circular saw unit 189 is moved in thefrontward/rearward direction at a position above the base 182 and theturntable 183. In such a miter saw 181, the angular rotation of theturntable 183 and the tilting motion of the circular saw unit 189 can beperformed in the manner similar to the foregoing embodiments. Accordingto this modification, since the circular saw unit 189 is movable infrontward/rearward direction, a workpiece having a greater size infrontward/rearward direction can be cut.

Further, various combinations are conceivable with respect to theabove-described modifications. Further, various modification can beeffected on the slide type miter saw 181.

1. A miter saw comprising: a base section that supports a workpiecethereon, the base section having a tilt support; a circular saw unitrotatably supporting a circular saw blade; a support section pivotallymovably supporting the circular saw unit at a position above the basesection, the support section having a tilting section laterallytiltingly movable together with the circular saw unit and supported tothe base section, the tilt support supporting the tilting section incontact therewith, the tilting section being tiltingly movable along atilting locus; a clamp mechanism that presses the tilting sectionagainst the tilt support for fixing a lateral tilting posture of thesupport section; a biasing member that provides a frictional forcebetween the tilt support and the tilting section so as to resistmovement of the tilting section; and a tilt amount fine control unitdisposed between the tilting section and the tilt support, where thetilt amount fine control unit allows adjustment of a fine lateraltilting posture of the support section while the frictional force isbeing applied between the tilt support and the tilting section by thebiasing member.
 2. The miter saw as claimed in claim 1, wherein the tiltamount fine control unit comprises: an arcuate section provided at thetilting locus and movable integrally with the tilting section; arotation shaft rotatably supported to the tilt support and associatedwith the arcuate section for tiltingly moving the tilting section; andan adjustment knob rotatably supported to the tilt support andassociated with the rotation shaft for rotating the rotation shaft aboutan axis thereof.
 3. The miter saw as claimed in claim 2, wherein therotation shaft is drivingly connected to the arcuate section, and theadjustment knob is drivingly connected to the rotation shaft.
 4. Themiter saw as claimed in claim 2, wherein the rotation shaft is movablebetween an associating position where the rotation shaft is associatablewith the arcuate section and a separated position where the rotationshaft is away from the arcuate section.
 5. The miter saw as claimed inclaim 2, wherein the clamp mechanism comprises a clamp shaft supportedto the tilt support, and wherein the adjustment knob is rotatablysupported on the clamp shaft.
 6. The miter saw as claimed in claim 2,comprising a digital display that displays a tilting angle of thetilting section relative to the tilt support.
 7. The miter saw asclaimed in claim 6, wherein the base section comprises a base, and aturntable supported on the base and rotatable about a rotation axisrelative to the base, the turntable comprising a circular table sectionhaving a front end and a rear end to which the support section issupported, and a neck table section extending frontwardly from the frontend in a diametrical direction of the circular table section, thedigital display being disposed at the neck table section.
 8. The mitersaw as claimed in claim 2, wherein the clamp mechanism is movablebetween a non-fixing position where the tilting motion of the tiltingsection relative to the tilt support is permitted and a fixing positionwhere the tilting section is in intimate contact with the tilt supportto prevent the tilting section from being tiltingly moved relative tothe tilt support, rotation of the rotation shaft being prevented onlywhen the clamp mechanism is at the fixing position.
 9. The miter saw asclaimed in claim 8, comprising a tilting motion restraining mechanismthat restricts the tilting motion of the tilting section relative to thetilt support when the clamp mechanism is at the non-fixing position. 10.The miter saw as claimed in claim 2, wherein the adjustment knobprovides a rotation angle greater than a tilting angle of the tiltingsection relative to the tilt support.
 11. The miter saw as claimed inclaim 1, wherein the support section comprises: a holder section havinga lower end supported to the base section and having an upper endprovided with a slide guide portion; and a slide section slidablysupported by the slide guide portion and extending in a directionparallel with a line which is an intersection of the base section andthe circular saw blade, the circular saw unit being pivotally movablysupported to the slide section.
 12. The miter saw as claimed in claim 1,wherein the tilt amount fine control unit comprises a gear mechanismincluding a gear portion that permits the tilting section to tilt a fineangle upon revolution of the gear portion, the gear mechanism beingconfigured to perform adjustment of a fine tilting angle throughout anentire tiltable region of the tilting section.
 13. A miter sawcomprising: a base section that supports a workpiece thereon, the basesection having a tilt support; a circular saw unit rotatably supportinga circular saw blade; a support section pivotally movably supporting thecircular saw unit at a position above the base section, the supportsection having a tilting section laterally tiltingly movable togetherwith the circular saw unit and supported to the base section, the tiltsupport supporting the tilting section in contact therewith, the tiltingsection being tiltingly movable along a tilting locus; a rotatable leverthat fixes the tilting section to the tilt support upon rotatingoperation; a biasing member configures to provide a frictional forcebetween the tilt support and the tilting section so as to resist amovement of the tilting section; and a rotatable adjustment knob movablealong with the tilting section and associated with the tilt support,where the rotatable adjustment knob allows adjustment of a fine lateraltilting posture of the support section while the frictional force isbeing applied between the tilt support and the tilting section by thebiasing member.
 14. The miter saw as claimed in claim 13, wherein thelever and the adjustment knob provide a relationship that allows anoperator to operate the lever at his one hand and to operate theadjustment knob at his another hand.
 15. The miter saw as claimed inclaim 13, further comprising a fine control unit comprising a gearmechanism connected to the rotatable adjustment knob, the fine controlunit including a gear portion that permits the tilting section to tilt afine angle upon revolution of the gear portion through operation of therotatable adjustment knob, the gear mechanism being configured toperform adjustment of a fine tilting angle throughout an entire tiltableregion of the tilting section.